Plastic drawer towers are most commonly made with a series of frames connected to each other. Each frame only accommodates a single drawer and has its own molded-in risers. A separate cover is connected at the top to enclose the drawers. In other drawer towers, the risers are molded separately and mechanically attach to the frames at both top and bottom. Drawers of different heights can be used in a single tower but each drawer requires a separate and unique frame. The frames of both aforementioned examples must be fastened together, increasing the number of parts required to assemble the drawer tower as well as increasing/decreasing the overall height of the unit.
The towers are labor intensive to assemble, require slides in the molds to form structure for a positive connection between parts, and need to have vertical draft to be molded, which precludes the front opening from being square with the drawer.
Drawers currently ride along their bottom surface making them difficult to open when they hold any substantial amount of weight since the weight that the drawer is carrying causes the bottom of the drawer to deflect downwards and catch on the frame below the drawer. Drawers that slide along their bottoms also tend to tip downward when opened. This causes the drawers to fall out of the frame. With the drawer open and loaded, the whole tower tips forward toward the user of the drawer.
Friction or interference fits to connect the components of the frames may simplify the mold. However, in some applications such friction fit components may not allow for a robust frame design that holds together well when moved.